Ultra high frequency switches



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ULTRA HIGH FREQUENCY SWITCHES 2 Sheets-Sheet 2 Filed May 2, 195a V? Ow lIIIIIIIIIIIIIIIII/IlfiflMl/I United States Patent 2,991,432 ULTRA HIGH FREQUENCY SWITCHES Pierre Tcheditch and Claude Beaugrand, Paris, France,

assignors to 'Compagnie Generale de Telegraphic Sans Fil, a corporation of France Filed May 2, "1958, Ser. No. 732,561 Claims priority, application France May 9, 1957 3 Claims. (Cl. 333-13) The present invention relates to transmit-receive or T-R switching devices for wave-guides used in radar systems.

Conventional devices of this type generally comprise a tight enclosure filled with a readily ionizable gas and having metal partitions into which windows, generally of glass, are built.

The provision of such enclosures presents in certain cases intricate problems as to the glass fixing and glassto-metal sealing. It is an object of the present invention to avoid such difiiculties by providing a directional coupler comprising a cylindrical tubular body, for instance of glass or quartz, closed at both its ends, to form a gas tight enclosure, mechanically applied to an opening in the common wall of two adjacent wave guides and dimensioned to provide a total directional coupling.

Such a. device is of a simple construction and the gas volume is larger than in conventional T-R switches of this type. The useful life of the tube is thereby considerably increased.

The invention will be best understood from the following description and appended drawing, illustrating an embodiment of the invention by way of a non-limitative example, wherein:

FIG. 1 illustrates schematically a T-R switching device of a known type;

FIG. 2 shows another type of a conventional switching device with its upper wall removed;

FIG. 3 is a cross-sectional view of the switch shown in FIG. 2, and

FIG. 4 is a perspective view in section of a switching device according to the present invention.

The T-R switch shown in FIG. '1 comprises a wave guide 1 which is coupled at one of its ends to a transmitter 4 and at the other to an aerial 5. A wave guide 2, one of the walls of which is adjacent to one of the walls of wave guide 1 or is common to both guides, is coupled at one end to a receiver and is closed at the other end by an absorption load 7. A portion of receiver guide 2 adjacent guide 1 is arranged to form a closed envelope 8 filled with a readily ionizable gas. A directional coupling window is built into the wall common to guides 1 and 2 and two windows 10 and 11 are respectively provided in the end walls of enclosure 8.

Windows 9, 10 and 11 are generally formed of glass plates and are tightly sealed into the corresponding metal walls. As is well known, such metal-to-glass sealings are of a rather delicate construction.

The same difficulty is encountered in the known device shown in FIGS. 2 and 3. In this device, an enclosure 33 is arranged between opposite walls of guides 31 and 32 which correspond to adjacent guides 1 and 2 of FIG. 1 and into which glass windows 34 and 35 are respectively sealed.

The sealing difiiculties mentioned above are particularly serious when comparatively long wave-lengths are concerned. Thus, when the operating wave-length is, for example, of the order of 23 cm. the dimensions of the guide are 165 mm. by 82.5 mm., and the windows necessary for providing a total coupling between the two guides must be 400 mm. long and have a maximum thickness 37 of 10 mm. Those are rather exacting requirements which it is difficult to meet on a commercial scale.

As already mentioned, the invention has as an object the avoiding of such difficulties.

According to the embodiment illustrated in FIG. 4, a simple cylindrical glass or quartz tube or wave energy permeable tubular enclosure 41, closed at its both ends and having a diameter substantially equal to the small dimension of guides 43 and 44 is used to provide a gas tight enclosure. Such tubes are easily designed and manufactured and filled with readily ionized gas.

It is of course, to be understood that the tube 41 need not have a circular cross-section and the terms tube or tubular are intended to include oval, polygonal and other types of cross-sections.

Tube 41 is applied to an opening 46 provided in wall 42 which is common to wave guides 43 and 44 by means of simple mechanical devices such as spring blades 45 and angularly shaped dielectric blocks or wedges 48 and 49. The diameter of tube 41 is slightly less than the corresponding dimension of wall 42.

Opening 45 is dimensioned, as well known in the art, to provide a total coupling between guides 43 and 44.

Elastic blades 45 are secured to the edges of window 46. They are applied on the glass tube along two generatrices of the cylinder along which the tube is metallized, as shown at 47, to assure a better electrical contact. The tube is, of course, filled with ionizable gas in a conventional manner.

It is to be understood that the invention is in no way limited to the embodiment illustrated, which has been described by way of example only.

What is claimed is:

1. A directional coupling switch for coupling two wave guides to each other comprising: a first and a second wave-guide portion having a common wall, said wall having an opening; a wave-energy permeable tubular enclosure, filled with ionizable gas and positioned in one of said wave-guides along said opening; and means for applying said tube against said wall at said opening to obturate the same.

2. A directional coupling switch for coupling two wave guides to each other comprising: a first and a second wave-guide portion having a common wall; said wall having an opening; a. wave-energy permeable tubular enclosure, filled with ionizable gas and positioned in one of said wave-guides, said tube having a diameter slightly less than the small dimension of said common wall; elastic blades extending along said opening in the same direction as said tube and contacting the same; and insulating blocks for wedging said tube against said blades.

3. A directional coupling switch for coupling two wave guides to each other comprising: a first and a second wave-guide portion having a common wall, said wall having an opening; a wave-energy permeable tubular enclosure, filled with ionizable gas and positioned in one of said wave-guides, said tube having a diameter slightly less than the small dimension of said common wall; and means for applying said tube against said wall at said opening to obturate the same.

References Cited in the file of this patent UNITED STATES PATENTS 2,814,784 Riblet Nov. 26, 1957 2,922,124 Braden Ian. 19, 1960 FOREIGN PATENTS 698,591 Great Britain Oct. 21, 1953 

